Roger Federer has been knocked out of the US Open in the fourth round on Monday by world number 55 John Millman.
The 37-year-old Swiss had prioritised winning a sixth title at Flushing Meadows but was beaten 3-6 7-5 7-6 (9-7) 7-6 (7-3) in three hours 38 minutes.
It is the first time Federer has lost to a player ranked outside of the top 50 at the US Open, the BBC reports.
Australian Millman will play two-time champion Novak Djokovic in his first Grand Slam quarter-final on Wednesday,
Second seed Federer, bidding for a record-extending 21st Grand Slam, missed set points in the second and third sets before capitulating in the fourth-set tie-break.
The Swiss legend, who had not dropped a set in his first three matches in New York, had 77 unforced errors and 10 double faults and landed just 49 percent of his first serves, according to a Reuters report.
Millman, 29, had never beaten a top-10 player before but suddenly found himself with five match points against arguably the greatest male player of all-time.
After Federer rallied to save two of the them, Millman completed victory at almost 01:00 local time in New York when the out-of-sorts Swiss lumped a forehand long.